Government forces have defeated Tamil Tiger rebels after surrounding them in Sri Lanka's northeast, Sri Lanka's President Mahinda Rajapaksa announced Saturday.

President Mahinda Rajapaksa attends the opening session of the World Economic Forum at the Dead Sea resort of Southern Shuneh in Jordan on Friday. (Mohammed abu Ghosh/Associated Press)

Speaking during a visit to Jordan, Rajapaksa said he would return Sunday to a country free from the "barbaric acts" of the militants — as "a leader of a nation that vanquished terrorism."

The development follows 25 years of civil war between the military and Tamil separatists.

Earlier in the day, the military said remaining fighters with the Liberation Tigers of Tamil Eelam (LTTE) were cornered in an area no larger than one square kilometre.

Government forces said they had seized the entire coastline along Sri Lanka's northeast, cutting off any possibility of an escape by sea.

The fate of LTTE leader Vellupillai Prabhakaran and other leaders who were surrounded is not known.

The military reported that fighting was still raging as evening came and that rebels were confined to a small sandy spit along the coast.

The Red Cross has warned of "an unimaginable humanitarian catastrophe" for the hundreds of wounded trapped without treatment in the battle zone.

Toll on civilians 'severe'

Aid groups said about 4,500 civilians escaped the area on Friday, but the United Nations estimates between 30,000 and 80,000 others remain.

"Conditions for the tens of thousands who are stuck in there are, at best, appalling," said UN spokesman Gordon Weiss, speaking from the capital, Colombo.

"There is a fully fledged battle going on between the remaining Tamil Tigers and government forces," he said. "All sorts of armaments are being used, right up until recent hours — heavy calibre weapons. And it's a tiny patch of land. It's perhaps a third of the size of Central Park in New York City.

"We have no idea just how many people have been killed and wounded, but just as we've seen in recent weeks, we suspect the toll on civilians as being severe," Weiss told CBC News.

More than 17,500 civilians have fled since Thursday, according to military spokesman Brig. Udaya Nanayakkara.

Canadian protests to continue

In Toronto, Tamils supporting the separatist cause have stepped up street demonstrations in the past two weeks in a bid to win foreign condemnation of government actions.

Thousand of Tamil demonstrators occupied parts of downtown Toronto for several hours Friday night. They began with a sit-in at Yonge and Dundas streets before moving to the U.S. consulate on University Avenue.

Their protests were expected to continue, with a candlelight vigil planned later Saturday in front of the U.S. consulate.

Last Sunday, about 2,000 demonstrators blockaded the city's Gardiner Expressway for six hours during a busy Mother's Day evening.

With files from The Associated Press